The challenge is the front and rear tires have a different diameter, and so if you put a front tire on the rear, then you will be running your two rear wheels at different rotational speeds.
The conventional wisdom here will say (and I’m not disputing it - I have no way to know) that this condition will put significant wear on the “limited slip” components in your ZF.
IIRC, it has been said that this can cause damage in less than 50 miles!
So that is a challenge to consider if you find an appropriate sized “space-saver spare”…. Maybe you want to see if you can match the REAR tire diameter, and then make sure it’s real skinny, in case you have to use it up front (don’t make any hard turns).
Rocky
PS…. I’m interested in other responses you will undoubtedly get on this subject!